Here's how to do it:
For To-Do's: press the Alt key, then type C M T
For Calendar: press the Alt key, then type C M C
For Email, hold Ctrl and press M
Edit your new document, then save and close (or send). It's that easy. Your Mail file doesn't even have to be open.
To discover even more Notes keyboard shortcuts, see here: Ramp up your workspeed with the most powerful key on your keyboard
Got any other favorite shortcuts? Feel free to share!
Here's something else I just discovered! There are shortcuts to open your Mail, Calendar, and Contacts from anywhere in Notes!
To open Mail: hold Ctrl and press 1